This invention relates to a method and apparatus for detecting the position of a take-up package during an automatic doffing and donning cycle. More specifically, the invention relates to a winder of the type wherein a number of empty take-up packages, such as winding tubes, are contained in a magazine which dispenses one of the tubes into a chuck during each doffing and donning cycle. The particular disclosure of this application is of a textile winder which is used to wind yarn onto take-up tubes suitable for further processing. However, the disclosure of this application can be utilized in other fields and, for this reason, relates broadly to strand processing.
The necessity of automating the winding process was recognized many years ago. In the past twenty years, many developments have been made relating to automatic doffing and winding of textile machines of various types. Automatic doffing and donning reduces the time between the winding cycles and greatly reduces the amount of manual labor required to service each machine. Ordinarily, donning takes place by dispensing a take-up package from a magazine onto an empty chuck. The chuck is then moved into position against a drive roller and the drive roller begins rotating. Frictional contact between the surface of the drive roller and the take-up package causes the take-up package to rotate, thereby winding yarn onto its surface. Since each take-up package is donned automatically, the machine is normally not attended. Therefore, if the package is improperly donned onto the chuck or if the supply of take-up packages in the magazine is exhausted, it is important that an indication of this condition be given so that the machine operator can correct the problem by properly donning a package and/or replenishing the supply of packages in the magazine.
Such a system should also permit individual positions to be locked out of operation when less than a full machine is being operated.
The design of the sensing mechanism should be simple and reliable. Use of certain types of components such as air cylinders, complicated electrical relays and the like should be minimized because of the necessity of frequent and sensitive adjustments and the susceptibility of such devices to malfunction because of environmental contaminants.